Chewing gums presently marketed are classified as sugar-containing and sugarless. The sugarless chewing gums include artificial sweeteners and/or sugar alcohols, such as sorbitol, mannitol and/or xylitol, as sugar and corn syrup substitutes. While the sugarless chewing gums may be classified as non-cariogenic, they are not non-caloric. The sugar alcohols have the same caloric content as carbohydrates, thus would not be a recommended item for the truly diet conscious.
The sugar-containing gums contain corn syrup as a softener or plasticizer and sugars such as sucrose, dextrose and/or fructose. These materials, which are carbohydrates, have a caloric value of approximately 4 calories per gm.
Accordingly, there clearly exists a need for a truly calorie-free carbohydrate-free chewing gum.
It has been suggested that a calorie-free gum may be produced by forming a chewing gum from gum base, flavor oil, softener (such as lecithin), spray-dried flavor, and artificial sweetener. Such a product is free of extractable sugar and calorie-containing sugar substitutes and therefore does not provide a fermentable substrate to promote glycolysis in the oral cavity. However, it has been found that such calorie-free gum is hard to chew, has poor texture, and is lacking in initial and subsequent flavor and sweetener release.
The reason that it is hard to chew and has poor texture is that it does not contain the usual soluble bulking agents, such as sugar or sorbitol, which impart necessary sweetness and discontinuity to the gum base upon chewing. Moreover, use of large amounts of softeners or plasticizers only imparts extreme softness to the gum base and not a desirable chew or textural quality.
Another problem encountered in both sugar-containing and sugarless chewing gum is that such gums adhere to artificial teeth and other surfaces. The interface between natural teeth and chewing gum is not one of tooth enamel (calcium phosphate) but rather mucin which is a slippery proteinaceous film covering natural teeth. However, it appears that artificial teeth and dentures, which are usually formed of acrylic polymers, polystyrene, polyvinyl chloride, polyvinyl esters (Luxene), hard rubber (Vulcanite), and the like, do not wet as effectively as natural teeth, and will not readily be coated with mucin. Accordingly, where many chewing gum compositions will not adhere to natural teeth, they will adhere to artificial teeth and dentures.
Various additives for chewing gums have been suggested to reduce or eliminate the problem of chewing gum adhering to dentures and artificial teeth, such as lecithin as disclosed in U.S. Pat. No. 2,197,719, lanolin as disclosed in U.S. Pat. No. 2,197,718 and silicone oils as disclosed in U.S. Pat. No. 2,761,782. U.S. Pat. No. 3,255,018 to Comollo discloses the use of water-soluble hydrolyzable tannin, such as tannic acid or polymer-tannic acid adducts, in combination with type A or B gelatin water-containing hydrophilic polymer gels.
U.S. Pat. No. 1,977,059 to Hatherell discloses a method of making a chewing gum base produced form resin, rubber, and other materials examples of which include fine fibers of a material such as wood or asbestos or cotton or silk. The latter materials are ostensibly present to impart cohesivity to the gum base.
Larger cud volume is a desired characteristic in chewing gums. Accordingly, increasing the cud volume without increasing the gum base is a very desired characteristic in chewing gums for economic and functional reasons. This is expecially true in bubble gum, since small cuds will not allow blowing bubbles.